title: Co-purification of alanine-glyoxylate aminotransferase with 2-aminobutyrate aminotransferase in rat kidney.
abstract: Alanine-glyoxylate aminotransferase and 2-aminobutyrate aminotransferase were co-purified from rat kidney to a single protein (about 500-fold purified from the homogenate). The activity ratios of alanine-glyoxylate aminotransferase to 2-aminobutyrate aminotransferase were constant during co-purification steps suggesting the 2-aminobutyrate aminotransferase activity was catalysed by only alanine-glyoxylate aminotransferase. The molecular weight of the enzyme was estimated to be approx. 213 000, 220 000 and 236 000 by analytical ultracentrifugation, Sephadex G-150 gel filtration and sucrose density gradient centrifugation, respectively. From the polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate, the enzyme consisted of four apparently similar subunits having a molecular weight of approx. 56 000. The enzyme was almost specific to L-alanine and L-2-aminobutyrate as amino donor and to glyoxylate, pyruvate and 2-oxobutyrate as amino acceptor. The enzyme was identified with rat liver alanine-glyoxylate aminotransferase isoenzyme 2 but not with rat liver alanine-glyoxylate aminotransferase isoenzyme 1 from Ouchterlony double diffusion analysis. Absorption spectra and some kinetic properties of the enzyme were clarified.
mesh_terms: D000612:4-Aminobutyrate Transaminase / Q000302:isolation & purification* / Q000378:metabolism; D000410:Alanine Transaminase / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D005779:Immunodiffusion; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D008970:Molecular Weight; D051381:Rats; D013379:Substrate Specificity; D000637:Transaminases / Q000302:isolation & purification*
chemical_list: D007527:Isoenzymes; D000637:Transaminases; D000612:4-Aminobutyrate Transaminase; D000410:Alanine Transaminase; C019635:Alanine-glyoxylate transaminase